Improvement in methods of refining cast-iron and making castings



PATENT QFFICE.

ZOHETH S. DURFEE, OF NEW YORK, N. Y.

IMPROVEMENT IN METHODS OF REFINING CAST-IRON AND MAKING CASTINGS.

Specification forming part of Letters Patent No. 118,597, dated August 29, 1871.

To all whom it may concern:

Be it known that I, ZOHETH S. DURFEE, of New York city, county and State of New York, have invented certain improvements in making castings of iron taken from the smelting-fnrnace in'which it has been made, of which the following is a specification:

Various attempts have been made from time to time to make castings from iron taken directly from smelting or blast-furnaces, but nearly or quite all such operations have been abandoned, because the crude-iron, run directly from the smelting-furnace or from ladles into which it had just been tapped into molds, was found to be too impure and too irregular in character to be relied upon for many of the castings desired.

Now, in order to obviate these disadvantages, and to be enabled to suitably refine the iron tapped out of the smelting-furnace and then cast it into any desired form without suffering it to cool and then remelting it, and also to be able to make conveniently mixtures of other irons with such iron as may be tapped from any smelting-furnace whose product it may be desired to cast without allowing it to cool and then remelting it, I proceed as follows:

I place at any convenient point near the blastfurnace, or within such distance that the crude metal tapped out from the blast-furnace can be carried thereto without losing its fluidity, a reverberatory or other suitable furnace, preferably a gas-furnace, such as the Siemens regenerative gas-furnace, or any similar furnace in which a high heat may be maintained at small cost of fuel, and in which the waste gases of the blastfurnace can be used as fuel in whole or in part, and I pour or run the metal tapped out from the blast-furnace therein.

A very desirable arrangement in connection with such a furnace is described in the specification of apatent sent by me to the Patent Office on the 14th February of this year, as such an apparatus will enable the purification of the metal treated to be easily effected by letting suitable fluxes pass with the metal into the furnace.

When the metal has been poured into the gasfurnace it can be treated in any desired way to refine it, and any metals or alloys of metal can be added at will. The iron in the gas-furnace can thus be kept at any given standard, and part of it tapped out from tiTne'to time, as may be required for making castings of any desired quality, and it will be seen that this plan ofiers great advantages for the manufacture of high grades of castings, such as car-wheels, malleable castings, &c., as the heat of the gas-furnace can be so far raised as to melt or keep melted the most decarbonized iron.

The gas-furnace may be of any desired capacity, or two or more such furnaces may be used together in making large castings.

In cases where transportation of castings from blast-furnaces to market would be inconvenient or too expensive I obtain some of the advantages ofthe foregoing process as follows: I combine with one or more reverberatory or gas-furnaces one or more cupola-furnaces, so arranged that the metal melted in the cupolas can be tapped and run into the other furnaces and from the latter into molds or into ladles for being poured into molds. In such cases I use the cupola-furnaces for melting pig-iron, and I prefer to melt therein the most inferior metal to be used, and also all metal the character whereof is not definitely known. The iron so melted will then be tapped into the gas or other furnaces and samples taken therefrom and tested, and thereupon it can be treated in any way to give it the desired qualities for any kind of casting.

It will be understood that the character of the iron in the gas-furnaces can be varied from time to time or kept continuously at one standard; and not only by this means may any desired uniformity or variety in the quality of the castings produced be attainable, but greater economy in cost because by this plan cheaper mixtures of pig-iron can be made for any given purpose than can be made in cupolas, and such mixtures can be more quickly and cheaply made than they can be by the use of the gas or reverberatory furnaces alone.

I am aware that it is not new to run or pour crude-iron from blast-furnaces into reverberatory furnaces for the purpose of puddling or refining it for being puddled or in otherwise treated for the manufacture of malleable iron and steel, and Imake no claim thereto; but I havenever known, heard, or in anywise ascertained that the plan herein proposed for cheapening the production and improving and regulating the quality of castings has ever before been proposed or practiced.

What I claim as my invention is 1. The continuous process, substantially as herein described, of treating iron taken directly from blast-furnaces and making castings therefrom.

2. The herein-described modes of treating iron for the manufacture of castings by first melting it in ordinary cupola-furnaces, and then, previously to founding it, tapping it into reverberatory furnaces and refining it or in otherwise modifying its character.

3. Oombiningreverberatory or gas-melting furnaces with blast-furnaces, substantially as and for the purposes specified.

4. Combining reverberatory or gas-meltingfurnaces and cupola-melting furnaces, substantially as and for the purposes specified.

ZOHETH S. DURFEE.

Witnesses:

OHs. H. LADDEN, EMIL HEUSNER. 

